Generally, this kind of speed control device is provided in proximity to the grip of the handle bar or at the bicycle frame, such as the top tube. In the former case, a driver operates the control lever by the fingers of his hand which grips the handle grip.
A conventional speed control device, however, provides the control lever with friction to overcome a spring force of a return spring at the derailleur, so that the control lever, when operated against tension of the return spring, should be given a force overcoming the force of the return spring and the friction of the control lever, and, when operated in the direction of the tension of the return spring, should be given a force overcoming the friction.
Accordingly, a relatively greater force is required to operate the control lever in either direction. Furthermore, the control lever, when disposed to facilitate its operation in one direction, conversely is not easy to operate in the other direction.